package vr.mall.testTwo;
 
import java.util.Collections;
 
import redis.clients.jedis.Jedis;
 
public class RedisTool {
 
    private static final String LOCK_SUCCESS = "OK";
    private static final String SET_IF_NOT_EXIST = "NX";
    private static final String SET_WITH_EXPIRE_TIME = "PX";
    private static final Long RELEASE_SUCCESS = 1L;
 
    /**
     * 尝试获取分布式锁
     * 
     * @param jedis 		Redis客户端
     * @param lockKey  		锁
     * @param requestId	 	请求标识
     * @param expireTime	超期时间
     * @return 				是否获取成功
     */
    public static boolean tryLock(String lockKey,String requestId, int expireTime) {
        Jedis jedis = RedisUtil.getJedis();
        String result = jedis.set(lockKey, requestId, SET_IF_NOT_EXIST,SET_WITH_EXPIRE_TIME, expireTime);
        RedisUtil.returnResource(jedis);
        if (LOCK_SUCCESS.equals(result)) {
            return true;
        }
        return false;
 
    }
 
    /**
     * 释放分布式锁
     * 
     * @param jedis
     *            Redis客户端
     * @param lockKey
     *            锁
     * @param requestId
     *            请求标识
     * @return 是否释放成功
     */
    public static boolean releaseLock(String lockKey,
            String requestId) {
        Jedis jedis = RedisUtil.getJedis();
        String script = "if redis.call('get', KEYS[1]) == ARGV[1] then return redis.call('del', KEYS[1]) else return 0 end";
        Object result = jedis.eval(script, Collections.singletonList(lockKey),
                Collections.singletonList(requestId));
        RedisUtil.returnResource(jedis);
        if (RELEASE_SUCCESS.equals(result)) {
            return true;
        }
        return false;
 
    }
 
}